The Supreme Court, in the 2014 Riley/Wurie case, decided that police must obtain a warrant to search the phone (or computer, presumably) of someone who is arrested; normally, police do not need a warrant to search people who are arrested.
Border searches are different, but both the Fourth and the Ninth circuits have ruled that border agents must have some reasonable suspicion in order to search phones and computers.
The Eleventh Circuit has ruled (on May 23, 2018), however, that border agents may search phones and computers without any particular suspicion.
Begin with: Who is copyright for?
Content creators? As a property right? Or all of us, content consumers, as an incentive for the creation of new content?
If you believe the latter, you are likely to prefer a Utilitarian approach to analyzing copyright ethics; the Deontological approach is quite difficult because of the need to weigh the interests of the copyright holder with society at large.
If you believe the former, then the Deontological approach makes sense, though the Utilitarian approach works too, with much the same argument as for other property rights.
Deontological theories
Utilitarianism
Other approaches
Religion
Wrong v Harm
Relativism
Intellectual Property revisited
Deontological perspective on copyright
For-profit infringement
Ethical arguments about copyright
RIAA lawsuits
Fair Use
Music sampling
Cariou v Prince
Criminal infringement